1. Field of the Invention
This invention relates to valves for control of liquid flow and, more specifically, to ball valves with enhanced performance.
2. Description of the Prior Art
A search of the patent art related to ball valves which are related to the subject matter of the present application revealed the following patents. None of them anticipate the claims of this application, for the reasons which are recited.
U.S. Pat. No. 1,044,311 (Wall) issued Nov. 12, 1912 fails to show a ball valve in which the ball is moved by direct contact between a rotatable cam lobe member to effect opening and closing of the valve. In Wall, ball 9 is raised and lowered by a plunger 19 moving in water discharging path 7. Such a structure will have the tendency to accumulate sediment in path 7 causing plunger 7 to stick in a partially upwardly extended position, thus preventing positive shut-off by ball 9. The present invention avoids that problem by eliminating passage 7 and having no sliding motion in a constricted area.
U.S. Pat. No. 1,005,044 (Koch) issued Oct. 3, 1911 has a constricted passage 7 and a plunger 20, being closely similar to the Wall patent. The distinctions between this invention and that in the Koch patent are similar to those recited in connection with the discussion of the Wall patent and need not be repeated. This invention assures positive closure, Koch doesn't.
U.S. Pat. No. 1,447,231 (Barry) issued Mar. 6, 1923 fails to show or suggest a ball valve in which the ball is in direct contact with the activating lobe of a cam member which, upon rotation, causes the selective opening and closing of the ball valve. A tube 20 is interposed between cam 25 and ball 16 in Barry. Tube 20 must slide in cock casing 14 in order to cause tip 21 to engage ball 16. Corrosion can, and is likely to, form on the outer surface of tube 20 and on the inner surface of casing 14 resulting in a non-positive seating of ball 16 in seat 17. This invention avoids that problem by having direct drive of the ball by the cam lobe.
U.S. Pat. No. 1,476,029 (Black) issued Dec. 4, 1923 fails to show direct driving contact between the cam lobe and the ball as claimed in this application. Instead there is interposed rod 30 which passes thru a recess 28 in bushing 10. This constricted region will be the situs of corrosion and sediment accumulation with a resulting sticking of valve stem 30 and an impositive closure of the valve. This invention avoids that problem by directly driving the ball from the cam lobe.
U.S. Pat. No. 1,496,317 (Johnson) issued June 3, 1924 fails to show or suggest a ball valve in which the ball is moved by direct contact with a cam lobe, as claimed for this invention. Further, plunger 7 in Johnson can suffer from corrosion on its cylindrical surface.
Such corrosion can result in plunger 7 sticking in casing 2 and an impositive closing of the valve. It is to be noted that the water pressure in Johnson tends to keep the valve open, whereas in this application, the water pressure keeps the valve closed. The higher the pressure, the tighter the seal, in this invention.
U.S. Pat. No. 3,024,799 (Flieder) issued Mar. 13, 1962 fails to show or suggest a direct cam-lobe driven ball in a ball valve. Instead, there is an intermediate rod 40 (in tubular form). Rod 40 must move within lower end portion 18 of housing 17 to move ball 23. All of the possibilities, previously discussed for sticking of the ball actuating rod and impositive valve closing exist in the device of Flieder. The large area of contact between casing 18 and tube 40 exacerbates the potential problems.